1. Field of the Invention
The present invention relates to an image-taking apparatus that generates image signals by forming a subject image on an imaging device through an image-taking optical system.
2. Description of the Related Art
There has been proposed an image-taking apparatus employing both a halogen lamp and a xenon tube as a source for auxiliary light (see Japanese Patent Application Publication No. 9-90480 for example).
In contrast, portable telephones equipped with a camera employ a power-thrifty LED as an auxiliary light source in recent years. Since the amount of light from such an LED is easy to control when compared to a xenon tube, techniques for controlling the amount of power emitted from an LED have been proposed and disclosed (see Japanese Patent Application Publication No. 2003-179808 for example).
However, the light emission power of LEDs is extremely small when compared to conventional xenon tubes. Therefore, if a light-emitting unit employing an LED is incorporated in a camera, auxiliary light for image taking cannot reach a subject located far away from the camera, which is a problem. Even if auxiliary light for image-taking emitted to a subject reaches the subject, the amount of such auxiliary light may not be enough, which leads to a shortage of the required amount of light. Nevertheless, if such an LED is used as a light source, recharge time required by a xenon tube can be saved, a light-emitting unit that quickly emits light can be realized, and an amount of light emitted within close range can be controlled which has been difficult in a xenon tube. For these reasons, it is absolutely desirable to employ an LED.